SANFORD, Fla. — A Florida jury acquitted George Zimmerman of charges of second-degree murder and manslaughter Saturday night in the shooting death of Trayvon Martin, a case that alternately fascinated and appalled large segments of a spellbound nation.

Zimmerman bowed his head in the moments before the verdict was read. As the judge confirmed the verdict with jurors, one of the six women in the jury sat with a face flushed with emotion.

After the jury filed out of the courtroom, the Zimmerman family’s row in the audience became a swirl of tears and hugs. A man sitting near Zimmerman’s mother, Gladys Zimmerman, slapped his hands together in joy and sobbed.

The jury deliberated for more than 16 hours over two days until 9:47 p.m. Saturday, when court officials announced that there was a verdict.

“The prosecution of George Zimmerman was disgraceful,” Zimmerman’s attorney Don West said after the verdict. Mark O’Mara, another Zimmerman attorney, wondered aloud at a news conference “how many civil lawsuits will be spawned by this fiasco.”

Outside, dozens of demonstrators, backlit by a sea of television camera lights, massed on the long lawn outside the Seminole County Circuit Courthouse. Some carried signs decrying “racial oppression” and demanding “Justice for Trayvon.”

In a somber post-verdict news conference, Benjamin Crump, an attorney for Martin’s family who led the early public relations push for Zimmerman’s arrest, said the teenager would go down in the annals of history “next to Medgar Evers and Emmett Till.” He was making a reference to African Americans killed in two of the most infamous slayings of the civil rights era.

Earlier Saturday, the jury had sent a note to Judge Debra Steinberg Nelson requesting clarification of instructions related to manslaughter, signaling that they were taking a hard look at the lesser of the two charges against the former neighborhood watch volunteer and sending a jolt through the courtroom and the crowd outside. Before starting deliberations, the jury was given a cautionary note by Nelson, who instructed them that “Zimmerman cannot be guilty of manslaughter by committing a merely negligent act or if the killing was either justifiable or excusable homicide.”

The saga of Zimmerman’s shooting of Martin, an unarmed African American teenager, filtered into the American vernacular, transforming “hoodie” sweatshirts into cultural markers and provoking a painful reexamination of race relations in this country. Even the racial and ethnic identity of Zimmerman — he has a white father and a Hispanic mother — demanded a reordering of conventional paradigms. He was frequently referred to as a “white Hispanic,” a term that, for some, reflected a newly blended America and, for others, felt like an uncomfortable middle ground.

Attorneys fought over Zimmerman’s fate in a heavily guarded and windowless fifth-floor courtroom, calling more than 50 witnesses during three weeks of testimony before a sequestered six-woman jury. Afternoon thunderstorms sometimes shook the building, but the participants could see nary a drop of rain as they relived the night in February 2012 when Zimmerman killed Martin after spotting the 17-year-old walking through his gated community in the rain.

A parallel trial seemed to be taking place outside that cloistered space, with running debate on cable television and the Internet spurred by live-streaming coverage of the trial that effectively turned millions of Americans into quasi-jurors armed with every minute detail of the case. Others jammed into the small courtroom, lining up each morning for the coveted 24 seats allotted to the public.

Zimmerman, 29, watched with a neutral expression, sitting in his customary position at the defense table in ill-fitting blazers that an older friend bought on sale at Men’s Wearhouse for him to wear at the trial. Once, he’d dreamed of becoming a policeman or a prosecutor, and at times, he seemed to be observing the proceedings with the detachment of a moderately engaged student. Only at breaks — when the jury had left the courtroom — did he sometimes let his blank stare crack a bit. He would circle the defense table giving congratulatory handshakes to his attorneys before being escorted by a bodyguard and court security officers to a waiting room down the hall.

Behind Zimmerman, on the opposite side of the courtroom, sat Martin’s parents — Tracy Martin and Sybrina Fulton. The father, whom Martin was visiting in Sanford on the night of his death, watched stoically, his emotions measured best by the slowing or accelerating speed of his jaw muscles as he ground through packs of gum.

Martin’s parents, whose presence throughout the trial lent a powerfully visceral note to the proceedings, were not in the courtroom when the verdict was read. Daryl Parks, a family attorney, said he advised them to stay home and attend church Sunday.

The images on the courtroom screen and those painted by the attorneys were sometimes too much to bear. Fulton, her hair pulled tightly into a bun on top of her head, stood and hurried out of the courtroom on Friday when O’Mara showed a photo of her 17-year-old son in death. She often turned away when close-ups of the bullet that pierced her son’s heart flickered onto the screen. She wiped tears during closing arguments.

Zimmerman’s parents were banned from the court during testimony because they were witnesses, but they took seats just a few steps away from Fulton across the aisle during closing arguments. (Martin’s parents were also witnesses, but they were allowed to watch each day because they were immediate family members of the deceased.) The two sets of parents had dueled inside the courtroom and outside it. The parents each testified that they heard their son crying for a help in the background of a key 911 call.

On April 11, 2013 — the first anniversary of Zimmerman’s arrest — Gladys Zimmerman issued an open letter, saying her son had been taken into custody “solely to placate the masses.” She was referring to large racially charged demonstrations, including a “Million Hoodie March,” that were organized to protest the initial decision of local authorities not to charge Zimmerman with a crime. Martin’s mother responded with a statement calling the assertion of Zimmerman’s mother “disingenuous and disrespectful.”

For all the talk of race outside the courtroom, its role inside the trial was muted — more subtext than central theme. None of the jurors were African American. Nelson, the stern judge overseeing the case, ruled that prosecutors could say Zimmerman – who has a white father and a Hispanic mother – “profiled” Martin but could not say he “racially profiled” the African American teen. The decision disappointed some African American leaders who had hoped the action inside the courtroom might deepen the national conversation about race that was happening outside the building.

Nelson, a former prosecutor who was appointed to the bench in 1999 by Gov. Jeb Bush, a Republican, sparred repeatedly with West, Zimmerman’s attorney. In one of the trial’s signal moments, Nelson stormed off the bench shortly before 10 p.m. while West was talking, abruptly ending a marathon evidence hearing.

Nelson ruled that jurors would not be allowed to see text messages found on Martin’s cellphone about fighting and guns because they could not be authenticated. “Why you always fighting?” a message from one of Martin’s friends said, according to a defense expert. West had been eager to introduce the texts to further the defense claim that Martin was the aggressor in the fight and that Zimmerman — whom a gym owner described as “soft” and unathletic — was overpowered by the tall and slender teenager.

O’Mara and West, a former rock-and-roll DJ with a shaved head and an imposing courtroom presence, succeeded in turning many of the state’s key witnesses into assets for the defense. They got John Good, a neighbor, to testify that he saw a figure in dark clothes (Martin’s hoodie was dark) straddling another person and doing a mixed-martial-arts-style “ground and pound” while “raining down blows.” They also got lead police investigator Chris Serino to testify that he believed Zimmerman’s self-defense account.

Local prosecutors had not pursued the case, but Florida Gov. Rick Scott (R) appointed a special prosecutor, naming State Attorney Angela Corey of Jacksonville, Fla., to oversee it. Corey’s assistants, who argued the case, often seemed to struggle with their own witnesses. Bernie de la Rionda, a veteran prosecutor with a booming voice and a penchant for making fun of his own baldness, tangled repeatedly with Serino. And he struggled with Shiping Bao, a medical examiner and key witness, who testified that Martin might have lived for up to 10 minutes after being shot.

The timing was important because Zimmerman had told police investigators that he spread Martin’s arms after the shooting to check for weapons, but the teen was found with his arms under his body. Bao’s assertion allowed the defense to suggest that Martin might have moved his hands in the moments before his death.

In their best moments, prosecutors were able to highlight inconsistencies in Zimmerman’s accounts of the shooting and build a narrative about him as “a wannabe cop” who shot Martin “because he wanted to, not because he needed to.” They had much to work with — police conducted several taped interviews with Zimmerman and recorded a reenactment — all without Zimmerman requesting an attorney. Prosecutor John Guy said it would have been a “physical impossibility” for Zimmerman to have reached behind his back for his concealed and holstered Kel-Tec 9mm handgun if he had been lying on the ground with Martin on top of him.

Vincent di Maio, a distinguished silver-haired forensic expert who entered the courtroom with a Panama hat in hand, spoke at length about the gunpowder tattoo that formed on Martin’s skin as the bullet entered Martin’s body. The appearance of the tattoo, di Maio testified, was unshakable proof of the defense claim that Martin was leaning over Zimmerman with his sweatshirt failing away from his chest when the shot was fired.

Even before the verdict was delivered, O’Mara might have summed it up best, saying two lives were changed forever on that rainy night in the Retreat at Twin Lakes. The question that lingered is whether America was changed, too.